feat(themes): per-theme rofi identities for nord/retro-82/lumon/kanagawa

Author a designed rofi.rasi whole-swap for the four remaining identity
themes, so all six now carry a distinct menu look (summer-day/night
already shipped their legacy ports). Each is built from the theme's
character rather than a legacy layout (their waybar overrides are
palette-only, so there was nothing to port):

- nord:     soft rounded "frost panel" — frost border, brighter-frost
            selection, aurora-purple prompt
- retro-82: sharp CRT terminal — square corners, amber-on-navy, a teal
            scanline underline, mono
- lumon:    clinical cyan "bezel" — thick cyan frame, a framed-not-filled
            readout inputbar, mono
- kanagawa: ink & paper — warm washi-paper frame, deep ink-well inputbar,
            crystal-blue wave selection

Each file is self-contained (it replaces the generated theme) and keeps
the element structure the theme-grid picker's per-invocation -theme-str
layers onto. rofi.nix needs no change — its existing themes/<slug>/
rofi.rasi probe whole-swaps when the file is present. All four parse
clean under `rofi -dump-theme`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/ROADMAP.md

@@ -91,11 +91,23 @@ how to override it. Items marked ✓ are shipped.
   logo button opens nomarchy-menu); the other four identity themes are
   palette recolors and already match. Remaining: a visual pass over all
   six on the live ISO
-- **Per-theme rofi identity:** the `themes/<slug>/rofi.rasi` whole-swap
-  ships, and summer-day/night carry their legacy designs (inverted window,
-  green inputbar, yellow bottom-border). Remaining: author `.rasi`
-  identities for the other four ported themes if/when they want one (the
-  generated palette theme is the default and looks fine)
+- ✓ **Per-theme rofi identity:** the `themes/<slug>/rofi.rasi` whole-swap
+  ships, and all six identity themes now carry a designed `.rasi`. summer-day/
+  night keep their legacy ports (inverted window, green inputbar, yellow
+  bottom-border); the other four were authored from each theme's character
+  (no legacy layout to port — their waybar whole-swaps are palette-only):
+  **nord** a soft rounded "frost panel" (frost border, brighter-frost
+  selection, aurora-purple prompt); **retro-82** a sharp CRT terminal (square
+  corners, amber-on-navy, a teal scanline underline, mono); **lumon** a
+  clinical cyan "bezel" (thick cyan frame, a *framed*-not-filled readout
+  inputbar, mono); **kanagawa** ink-and-paper (warm washi-paper frame, a
+  deeper ink-well inputbar, crystal-blue wave reserved for the selection).
+  Each is self-contained (it replaces the generated theme) and keeps the
+  element structure the theme-grid picker's per-invocation `-theme-str`
+  layers onto; all four parse clean under `rofi -dump-theme`. The generated
+  palette theme stays the default for the other 15 presets. Remaining: a
+  visual pass over the four on hardware (the parse check confirms syntax, not
+  aesthetics).
 - ✓ **Visual theme picker (preview thumbnails):** `nomarchy-menu theme` is now
   a rofi **icon grid of real desktop previews** instead of a plain-text list —
   each theme a screenshot of its themed desktop (waybar + floating terminal),